Glutamate flavoring
The result is actually a chemical equilibrium among several ionized forms, including zwitterions, that depends on the pH (acidity) of the solution.
Only the glutamate ion is responsible for the umami flavor, so the effect does not depend significantly on the starting compound.
In 1907, Japanese researcher Kikunae Ikeda of the Tokyo Imperial University identified brown crystals left behind after the evaporation of a large amount of kombu broth as glutamic acid.
This is classified as one of the five basic tastes (the word "umami" is a loanword from Japanese; it is also referred to as "savory" or "meaty").
[10][11] Japanese cuisine originally used broth made from kombu (kelp) to produce the umami taste in soups.
The flavor enhancing properties of glutamic acid allowed Romans to reduce the use of expensive salt.
[20] The controversy surrounding the safety of MSG started with the publication of Robert Ho Man Kwok's correspondence letter titled "Chinese-Restaurant Syndrome" in the New England Journal of Medicine on 4 April 1968.
[24][20] This letter was initially met with insider satirical responses, often using race as prop for humorous effect, within the medical community.
[22] During the discursive uptake in media, the conversations were recontextualized as legitimate while the race-based motivations of the humor were not parsed, which replicated historical racial prejudices.
[22] Despite the resulting public backlash, the Food and Drug Administration (FDA) did not remove MSG from their Generally Recognized as Safe list.
[25][26][27][28][29] Herein, specifically East Asian cuisine was targeted, whereas the widespread usage of MSG in Western processed food does not generate the same stigma.
[30] These kind of perceptions, such as the rhetoric of the so-called Chinese restaurant syndrome, have been attributed to xenophobic or racist biases.
"[38] In 2020, Ajinomoto, the leading manufacturer of MSG, and others launched the #RedefineCRS campaign, in reference to the term "Chinese restaurant syndrome", to combat the misconceptions about MSG, saying they intended to highlight the xenophobic prejudice against East Asian cuisine and the scientific evidence.
[40] In 1959, the U.S. Food and Drug Administration (FDA) classified monosodium glutamate as generally recognized as safe (GRAS).
One such review was by the Federation of American Societies for Experimental Biology (FASEB) Select Committee on GRAS Substances.
In the European Union, these substances are regarded as "flavor enhancers" and are not allowed to be added to milk, emulsified fat and oil, pasta, cocoa/chocolate products and fruit juice.
The EU has not yet published an official NOAEL (no observable adverse effect level) for glutamate, but a 2006 consensus statement of a group of German experts drawing from animal studies was that a daily intake of glutamic acid of 6 grams per kilogram of body weight (6 g/kg/day) is safe.
Examples include tomatoes, cheeses, meats, hydrolyzed protein products such as soy sauce, and autolyzed yeast extracts.
As of 2002[update], the National Academy of Sciences Committee on Dietary Reference Intakes had not set a NOAEL or LOAEL for glutamate.
